Art of insulation and fireproofing



Oct. 23, 1934. R. E. BENNETT i 1,978,125

ART OF INSULATION AND FIREPROOFING Filed Aug. 19, 1929 FZEI- m @4M/L,MVM

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`Patented Oct.. 23, 1934 V1,978,125 l ART oF INSULATION AND maEPaoomNGRalph E. Bennett, Evanston, Ill., assi gnor to Sprayo-Flake Company,Milwauk, Wis., a M y poration of Wisconsin Appiieation August 19, 1929,serial No. 387,022

This invention relates to the art of insulation and has particularreference to the incorporation of a ilre resistant material into a mat.pro-

4duced in accordance with the disclosure of United 5 States LettersPatent to Edwin H. Wenzel and Maximillian P. Janisch, No. 1,718,507,dated June 25, 1929. p

'I'he insulating mat to which this invention particularly relates ispneumatically projected directly upon the surface to be.insulatedagainst the `passage of heat or sound. A stream of comminuted particlesof brous material, preferably in sheets, such as paper or the like ismoistened in mid air with an adhesive binder such as sodium silicate orsome other `material having similar characteristics. Under suchcircumstances, the paper or other comminuted material used in practicingthe process reaches the wall surface immediately after coming in contactwith the binder and, consequently the binder becomes effective almostinstantaneously to secure the ilbrousv particles in place, eitherAagainst the wall or against other similar particles previouslyprojected. 25 There are numerous lire proofing materials which are wellknown and frequently used to render other substances fire resistant.."lm# monium, sodium, borax and alum salts andmiscellaneous othersubstances are frequently used. The present invention contemplates theuse of any fire proong substance which will not interact chemically withthematerials used .for insulation and which is sufiiciently cheap to beeconomically serviceable and which is free of objectionablecharacteristics, such as the release of 'ammonia sometimes occurring inthe use of ammonium sulphate for this purpose. y All of the saltscommonly used'in iire proofing are readily soluble in water and have theproperty of ionization, being electrolytes. Sodium silicate, and otheradhesive binders used in the above described insulating process, ofwhich sodium silicate will be treated as a typical example, are colloidsand extremely susceptible to precipitation upon the introduction ofhighly ionized foreign substances, evenwhere l no physico-chemicalchangegesults. The'admixture of borax, ammonium phosphate, sodiumtungstate, magnesium sulphate, and the like with water-glass orsodiumsilicate will almost incidentally produce precipitation orljelling of the colloid resulting in separation of a voluminous mass ofhydrated silica. 4This makes it impossible to handle the sodium silicateas a liquid.

It also destroys its adhesive or bonding properties, rendering it untfor use in the-practice of the process above described. `These factssuggest the impossibility of using any ofthe well known iireprooiingLagents in a process where admixture with a colloid binder is'essential;but 60 the process hereinafter, described is directed to ward a solutionof this problem which will and does permit ordinary re proofing salt tobe employed notwithstanding the use of such a binder as sodium silicate.

The object of the present invention is to provide a process in which reprooiin'g chemicals may be employed as eectively as if mixed with theliquid adhesive but Without destroying or materialiy impairing theadhesive qualities of the sodium silicate 'or like substance used, andwith results which are otherwise benecial rather than harmful inthepractice of insulating proc-- esses.

In the drawing:

Figure 1 shows in section through three stories of a factory, theelevation of an apparatus suitable for use in practicing the presentinvention to the point Vof preparing -the fire poong material for use. f

Figure 2 is a diagrammatic elevation of apparatus employed in the actualuse of the fire proofing material in accordance with this invention.

, Like parts are identified by the samereference characters throughoutthe several views.

The invention contemplates the admixture of la dry salt used for reproofing purposes with the kdry comminuted paper or other like materialto be employed in the insulation process. To this end the salt,preferably magnesium sulphate (because of low cost, ease of handling andabsence of undesirable effects) is fed from the container 5 throughhopper '6 to the chopper 7 in which papers fed frompthe table 8 are comminuted preparatory to delivery of the brous particles by the centrifuge9 to the separator 10.V

In the separator the air passes olf and the magnesium sulphate andpaper'particles thoroughly mixed in the chopping operation are fed bygravity through pipe 11 to the commercial pack- 10 -ers 12 in which thecommingled salt and paper particles are bagged for delivery to the pointwhere the insulation is to be made. 'I'he packers 12 are similar tothose commonly used forbagging bran and the like.

On the job, the salt and paper mixture is introduced into hopper 15 from`which it is fed as required by the feederv 16y througha blower `fan 17which furnishes the pneumatic pressure for projecting the particles/in astream 18 from 11( ltiti this desirable objective.

nozzle 19 upon the wall surface 20 to be insulated. At the' time themagnesium sulphate and paper particles are projected from the nozzle 19they are entirely dry.

Air supplied from acompression tank 21 is led through hose 22 to thespray nozzles 23 which are also supplied with adhesive through hose 2dwhich leads from a tank 25 in which adhesive is subjected to pressure byair from the source at 21.

The spray of liquid sodium silicate from nozzles 23 creates a mistthrough which the particles of paper or other fiber sheets and thecrystals of magnesium sulphate or other insulating salt must pass. Intraversing this spray the paper and salt crystals are moistened by thesodium silicate which, for the rst time in mid air is exposed to theaction of the salt. Almost immediately thereafter the adhesive coatedpaper reaches the' surface upon which it is being `projected and isbonded thereto.

It has been found that in the exceedingly short space of time betweenthe admixture of adhesive and fire proofing material before the adhesivefunctions as a binder the re proofing material does not cause anybreaking down of the colloid to such a degree as to interfere with thebonding of the paper particles to each other and to the wall. In fact ithas been Afound that the setting of the bond is not only as effectivebut takes place more speedily than is the case where the re proofingmaterial is not used. It is supposed that the fire proofing materialdissolves itself in that portion of the moisture in the sodium silicatewhich penetrates the pores of the paper and that this results inpartially drying the adhesive on the surface of the paper particles,thereby promoting the hardening of the thin lm of adhesive before the reproofing salt can act thereon to break down the colloid.

In the patent above referred to, mention is made of the advantage ofhaving the adhesive binder as dry as possible at the moment ofengagement of the coated particles with each other. Apparently the useof a re proofing salt as magnesium sulphate in the manner hereindisclosed promotes In any event it is observed that the insulating matsets more speedily when the salt is used than when it is not and theadherence of the particles to each other and to the wall is notweakened, this result being contrary to what might be expected in anyadmixture of magnesium sulphate with sodium silicate.

The proportions of the fire proofing chemical employed are not importantto the result. The chemical may be used in any proportions desired forthe proper fireproofing effect within the range permitted by suchsecondary factors as cost. From fifteen to twenty-five per cent of thechemical as compared with the weight of paper used gives a verysubstantial re proofing effect, the nre resistance of the paper matbeing sufficient for all practical purposes. The mat produced when thisamount of chemical is employed doubtless contains some precipitation ofsilicate and is slightly more rigid and firm than a mat produced withlesser quantities of fire proofing salt, or none at all. For mostpurposes this rigidity is an asset rather than a liability.

While the disclosure relates particularly to a process of fire proofinga mat of this character, the same process may obviously be employed inthe use of salts for other purposes such as sodium fluoride or the likewhich 'would repel vermin.

f The process is directed broadly, therefore, to the Lerares admixtureof any colloid adhesive binder with any salt calculated to destroy thecolloid, under such circumstances that the mixture occurs drectly on thesurface of the material to be bonded and under conditions such that thebreaking down of the colloid, if any, will be insufcient to impair itsvalue as a binder, and will actually facilitate the set of the mat andrigidify it.

I claim:

1. The process of mixing a salt with solid particles and a. liquidbinder therefor subject to breakdown when mixed with said salt, whichprocess consists in projecting such particles in a previously preparedadmixture with said salt upon the surfaces to which said particles areto be bonded and the treatment of said particles and salt in the courseof such projection and substantially at the point of contact of saidparticles with said surfaces with relatively small quantities of saidbinder whereby said binder is immediately thereafter employed as a bondfor said particles.

2. The process of incorporating a salt in a mat of solid particles and abinder subject to breakdown in solution with said salt, which processconsists in the previous admixture of said particles with said salt, thepneumatic projection of the mixture of said particles and salt upon thesurface upon which said mat is to be formed and the projection of saidbinder in the form of a spray in the path of pneumatic projection ofsaid mixture.

3. The process of incorporating a fire proofing salt in a solid mattermade up of fibrous particles and a colloidal binder subject to breakdown when mixed with said salt, which process consists in treating saidparticles with said salt, projecting the mixture of said particles withsaid salt upon the surface to which said mat is to be applied andspraying the mixture of particles and salt with the binder in asubstantially continuous operation in which said binder is renderedeective as a bond for said particles prior to material breakdown in thepresence of said salt.

e. The process of incorporating a re proofing salt in an insulating matmade up of fibrous particles mounted with an initially liquid colloidbinding material subject to breakdown in the presence of fire proofingsalts, which process consists in the preliminary mixture of the fibrousparticles with the salt in dry form, the projection of such mixture uponthe surface to be insulated and the spraying of the binding material inthe path of projection of such mixture, whereby it is simultaneouslyapplied to the salt and to said particles and immediately thereafteremployed as a bond for said particles and before such breakdown of saidbinder can occur.

5. The process of building an insulating mat upon the surface to beinsulated, which consists in pneumatically projecting directly upon saidsurface particles of insulating material and a dry salt previously mixedtherewith, and the spraying of liquid binder in the path of projectionof such material upon said surface, whereby to treat said particlessuperficially with said binder in the presence of said salt, said saltbeing adapted partially to withdraw the water from said binder wherebyto facilitate the setting thereof.

6. The process of constructing a fire resistant insulating-mat directlyupon the surface to be insulated, which consists in a preliminarymixture of re proofing salt with fibrous particles of insulatingmaterial in dry form, the pneumatic of insulating material in dry form,the pneu-4 to be insulated and the spraying of a liquid binder in thepath of projection of lsaid material, whereby superiiciaily to coat saidparticles in the presence of said salt, said salt having the faculty ofabsorbing a portion of the. moisture of said binder, whereby tofacilitate the setting thereof. v 7. The process of constructing a fireresistant insulating fmat-directly upon the surface to be insulated,which consists in a preliminary mixture of fire proofing salt withfibrous 4particles matic projection of the dry mixture toward thesurface to be insulated and the sprayingvofra vus RALPH E. BENNETT..

